The invention relates to an arrangement for the active adjustment of a motor vehicle wheel having an adjusting element, suspension links linked to a wheel carrier, and an intermediate element for linking the adjusting element and the suspension links to the wheel carrier.
A wheel, suspension system disclosed in DE-PS 31 39 792 which shows an adjusting device for the camber change and the toe change under certain driving conditions. The adjustment takes place by way of hydraulic cylinders which are partially integrated into the link therebetween or which are formed as part of the wheel suspension link or as part of the link bearing. The adjustment elements are consequently subjected to relatively high forces which otherwise are absorbed only by the link bearings.
In Patent Document GB-A-2 203 711, an arrangement using a connecting link is shown for the control of the camber of the rear wheels for vehicles with four steerable rear wheels. This connecting link is pivotally fastened to the vehicle body and has a central swivel bearing for a suspension link supported and disposed on the wheel carrier. A hydraulic cylinder, which is constructed as an adjusting element and which causes the camber change of the wheel by way of the connecting link, is applied to the lower end of the connecting link facing away from the bearing of the body.
It is an object of the invention to provide a wheel suspension system for a motor vehicle which has a wheel adjusting device that requires little space, has a favorable response characteristic and is not subject to excessive forces.
According to the invention, this object is achieved by an arrangement for the active camber and/or toe adjustment of a motor vehicle wheel by a way of and adjusting device comprising an adjusting element in which suspension links are linked to a wheel carrier, are swivellably held on the vehicle body and the adjusting element, by way of a connecting intermediate element, is connected with the wheel carrier while acting upon it in an adjusting manner, wherein the intermediate element, by way of a central ball joint, is linked directly to the wheel carrier in a tiltable manner, and a control rod of the adjusting device is connected with a first bearing, and the suspension link is connected with a second bearing, the adjusting device comprising a hydraulic adjusting element which is connected with the control rod and being constructed to be capable of moving in and out while influencing the position of the wheel by way of an electronic control unit for forced wheel position changes as a function of driving parameters, such as suspension travel, lateral acceleration, the speed, the longitudinal acceleration, deceleration, yawings and steering angles and wherein the wheel is adjustable about a swivel axis formed below the wheel spin axis by a wheel-carrier-side tie rod joint and a wheel-carrier-side link joint.
According further to the present invention, the control rod can be held on the intermediate element which is linked to the wheel carrier and which holds on its upper free end the control rod in the swivel bearing with an axis in an articulated manner, and supports on its lower free end the suspension in the bearing with a swivel axis.
According further to the present invention, the control rod can be held on an intermediate element which is linked to the wheel carrier and which supports on an upper free end of the intermediate element the suspension link in the swivel bearing and holds on a lower free end of the intermediate element the control rod in the bearing in an articulated manner.
According further to present invention, between the adjusting element and the control rod, an intermediate lever is arranged which comprises two arms which are disposed at an angle with respect to one another. The intermediate lever with the arms which are disposed at different angles with respect to one another can be assigned to each wheel side of an axle between the control rod and the adjusting link.
According further to the present invention, the setting on the swivel shaft can be determined by the position of the wheel-carrier-side joint of the lower suspension link and by the position of wheel-carrier-side joint of the tie rod and a ratio of the camera to the toe-in on the wheel can be determined in a defined manner.
According further to the present invention, the swivel axis has a setting of alpha .alpha.=90.degree. for achieving a toe-in adjustment on the wheel.
According further to the present invention, the adjusting element is disposed in a plane arranged below the wheel spin axis and is connected with a two-arm lever which extends in an approximately vertical plane and is connected by means of its free end facing away from the bearing of the adjusting element with the control rod which is linked to the wheel carrier by way of the bearing above the wheel spin axis.
According further to the present invention, an adjusting device for absorbing the suspension travel is connected with the suspension link of each wheel side of an axle arranged below the wheel spin axis, the adjusting device being connected by way of one pressure pipe respectively with a chamber of the hydraulic cylinder.
The principal advantages achieved by the invention are that by the linking of the suspension element to the wheel carrier, which is separate from the control rod of the adjusting device, the forces, particularly the longitudinal forces, can also be absorbed separately, so that a wheel adjustment, such as a camber, a toe-in and a toe-out, is to be carried out which is not affected by it. As a result, a faster build-up of side force takes place, particularly during cornering and/or lane changes. During straight-ahead driving and particularly in connection with high speeds, a lower tire pressure may be used as a result of minimal wheel adjustment changes by way of the spring deflection, which clearly increases the comfort level.
The adjusting device for the wheels of an axle is constructed such that is can be used for the rear axles as well as for the front axles. A wheel adjustment takes place in a simple manner by way of a hydraulic cylinder, but may also take place by way of a motor, such as an electric motor or a motor that is driven in another manner.
By way of a rocker lever disposed on the wheel carrier by means of a ball joint, the control rod of the adjusting device as well as a suspension link are arranged to be pivotable about a horizontal axis which extends in the longitudinal direction of the vehicle. This double bearing results in an absorbing of the longitudinal forces only by way of the link bearing, and the tie rod bearing is free of loads resulting from these forces.
The connection of the control rod of the adjusting device with the adjusting link may take place by means of a two-armed supported lever. This lever then provides the possibility of determining the wheel adjusting paths in which the angle between the two lever arms, which are at an angle, is enlarged or reduced. As a result, the wheels can be adjusted in different fashions during the driving operation which is an advantage particularly during cornering in order to build up different cornering forces.
The adjusting device is also suitable for vehicles with rear wheel steering in the case of which, by way of the lower suspension link, a tie rod for a steering gear is also held on the wheel carrier.
In the case of vehicles with a rear engine, there is, for reasons of space, no room for an adjusting device arranged above the wheel spin axis. This adjusting device will then be arranged below the wheel spin axis, and a connection with the control rod arranged above the wheel spin axis will then take place by means of a deflecting lever.
The adjusting element, such as a hydraulic cylinder or a motor, may be controlled by means of an electronic control unit which processes the individual driving parameters. The individual driving parameters may be used as well as especially combined driving parameters and all driving parameters together.
As a function of the wheel adjustment with respect to suspension movements of the wheel, the lower suspension link, for example, may be connected with a device which absorbs the spring travel and correspondingly controls the hydraulic cylinder to carry out wheel adjustment changes.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.